1. Field of the Invention
The present invention relates generally to a photographic camera with autofocus and more particularly to an autofocus camera where the subject is highlighted in the viewfinder.
2. Discussion of the Background
Cameras are known which both record an image on photographic film and also produce an image electronically. In general, these cameras include not only traditional optics and film handling mechanisms for the film but also include a solid state imager to view the image electronically. The electronic image may be used to autofocus, to meter the scene lighting or to preview a scene before exposing the film or also to review a shot following the exposure to ascertain that the composition in the picture is correct.
U.S. Pat. No. 4,742,369 shows a camera having both photosensitive film and a solid state image element. This camera as well as other prior art includes basically two separate systems to record the film and the electronic image.
A more advanced camera has recently been described in copending U.S. application Ser. No. 288,887, now U.S. Pat. No. 4,949,117. In this device, the electronic and film recording mechanisms are integrated so as to form a less expensive and less complicated device. This camera also has a number of functions which are controlled by the solid state image sensor. Thus, functions such as exposure control and autofocus can be accomplished. Furthermore, the image sensed electronically can also be displayed to the operator. However, this camera does not provide for an additional indication of the subjects which are in the depth of field of the camera at the time of film exposure.
Thus, in prior art devices, it is usually necessary for the operator to determine whether the depth of field is sufficient by observing that the subjects of interest are not blurred in the viewfinder. However, this is a difficult task since, in a depth of field preview mode, the image may be generally dim and thus hard to clearly observe and especially difficult to determine the amount of blur of the subject as compared to the background. Thus, it is often difficult for operators to determine that the proper subjects are in focus.